C#—文件读写

短命女 2022-09-21 15:27 189阅读 0赞

/*
     * 启动窗体后，单击“保存文件”，打开“保存”对话框，将richTextBox里保存的文件保存到指定位置。
     * 单击“打开文件”菜单，将指定的文件内容读取到rithTextBox里。
     */
    using System;
    using System.Collections.Generic;
    using System.ComponentModel;
    using System.Text;
    using System.IO;
    using System.Windows.Forms;
    
    namespace WindowsFormsApplication2
    {
        
        public partial class Form1 : Form
        {
            public Form1()
            {
                InitializeComponent();
            }
    
            private void Form1_Load(object sender, EventArgs e)
            {
    
            }
    
            private void 打开文件ToolStripMenuItem_Click(object sender, EventArgs e)
            {
                if (openFileDialog1.ShowDialog() == DialogResult.OK)
                {
                    string filename = openFileDialog1.FileName;
                    this.richTextBox1.Text=RWFFilebyFileStream.Read(filename);
                    MessageBox.Show("打开成功");
                }
            }
    
            private void 保存文件ToolStripMenuItem_Click(object sender, EventArgs e)
            {
                if (saveFileDialog1.ShowDialog() == DialogResult.OK)
                {
                    string filename = saveFileDialog1.FileName;
                    RWFFilebyFileStream.Write(filename, this.richTextBox1.Text.Trim());
                    MessageBox.Show("保存成功");
                }
            }
    
            private void 退出ToolStripMenuItem_Click(object sender, EventArgs e)
            {
                Application.Exit();
            }
        }
        public class RWFFilebyFileStream
        {
            public static void Write(string strFile, string strText)
            {    //利用FileStream写文件
                FileStream fs = new FileStream(strFile, FileMode.Append, FileAccess.Write);
                UTF8Encoding tmp = new UTF8Encoding();
                byte[] b = tmp.GetBytes(strText);
                fs.Write(b, 0, b.Length);       //将内容写入文件中
                fs.Dispose();
            }
    
            public static string Read(string strFile)
            {
                FileStream fs = new FileStream(strFile, FileMode.Open, FileAccess.Read);
                long i = fs.Length;
                byte[] b = new byte[fs.Length];
                fs.Read(b, 0, b.Length);        //将文件内容读取到字节数组b中
                fs.Dispose();
                UTF8Encoding tmp = new UTF8Encoding();     //UTF8是一种编码模式，能将字节流转换为字符串
                return tmp.GetString(b);
            }
        }
    }

运行结果：

![Center][]

/*
     * 利用StreamReader类，读取文件内容并显示在ritchTextBox控件中。
     * 利用StreamWriter类，将ritchTextBox控件中内容写入文件。
     */
    using System;
    using System.Collections.Generic;
    using System.ComponentModel;
    using System.Data;
    using System.IO;
    using System.Linq;
    using System.Text;
    using System.Windows.Forms;
    
    namespace WindowsFormsApplication3
    {
        public partial class Form1 : Form
        {
            public Form1()
            {
                InitializeComponent();
            }
    
            private void Form1_Load(object sender, EventArgs e)
            {
    
            }
    
            private void button1_Click(object sender, EventArgs e)
            {
                if (openFileDialog1.ShowDialog()==DialogResult.OK)
                {
                    string fileName = openFileDialog1.FileName;
                    textBox1.Text = fileName;
                    StreamReader sr=new StreamReader(fileName,Encoding.GetEncoding("gb2312"));
                    string line;
                    while ((line=sr.ReadLine())!=null)   //读入文件下一行不为空
                    {
                        this.richTextBox1.Text += line + "\r\n";    //读一行，换行
                    }
                    sr.Close();
                }
                
            }
    
            private void button2_Click(object sender, EventArgs e)
            {
                if (saveFileDialog1.ShowDialog()==DialogResult.OK)
                {
                    string fileName = saveFileDialog1.FileName;
                    textBox1.Text = fileName;
                    StreamWriter sw = new StreamWriter(fileName);        //制定写入流
                    sw.Flush();            //清理缓冲区
                    //写入内容
                    sw.BaseStream.Seek(0, SeekOrigin.Begin);
                    sw.Write(richTextBox1.Text);          //将richTextBox内容写入文件
                    sw.Close();
                }
            }
        }
    }

运行结果：

![Center 1][]

![Center 2][]

[Center]: /images/20220721/5d97cd997a1b456cbce06081d194e2e1.png
[Center 1]: /images/20220721/7c67168e89ca4d7d9406e1dce2252dba.png
[Center 2]: /images/20220721/c66c9e8275654f77bc7bfe87f91f7bf5.png